Over a century of detection and quantification capabilities in analytical chemistry--historical overview and trends.

The detection limit (LD) and the quantification limit (LQ) are important parameters in the validation process. Estimation of these parameters is especially important when trace and ultra-trace quantities of analyte are to be detected. When the apparatus response from the analyte is below the detection limit, it does not necessarily mean that the analyte is not present in the sample. It may be a message that the analyte concentration could be below the detection capabilities of the instrument or analytical method. By using a more sensitive detector or a different analytical method it is possible to quantitatively determine the analyte in a given sample. The terms associated with detection capabilities have been present in the scientific literature for at least the past 100 years. Numerous terms, definitions and approaches to calculations have been presented during that time period. This paper is an attempt to collect and summarize the principal approaches to the definition and calculation of detection and quantification abilities published from the beginning of 20th century up until the present. Some of the most important methods are described in detail. Furthermore, the authors would like to popularize the knowledge of metrology in chemistry, particularly that part of it which concerns validation of the analytical procedure.